On Tue, 18 Jun 2019, Ming Lei wrote:
> From: Finn Thain <fthain@xxxxxxxxxxxxxxxxxxx>
>
> Use the scatterlist iterators and remove direct indexing of the
> scatterlist array.
>
> This way allows us to pre-allocate one small scatterlist, which can be
> chained with one runtime allocated scatterlist if the pre-allocated one
> isn't enough for the whole request.
>
> Finn added the change to replace SCp.buffers_residual with sg_is_last()
> for fixing updating it, and the similar change has been applied on
> NCR5380.c
>
> Cc: Finn Thain <fthain@xxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
Signed-off-by: Finn Thain <fthain@xxxxxxxxxxxxxxxxxxx>
> ---
> drivers/scsi/aha152x.c | 46 +++++++++++++++++++++---------------------
> 1 file changed, 23 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/scsi/aha152x.c b/drivers/scsi/aha152x.c
> index 97872838b983..f07f3fa9b58d 100644
> --- a/drivers/scsi/aha152x.c
> +++ b/drivers/scsi/aha152x.c
> @@ -948,7 +948,6 @@ static int aha152x_internal_queue(struct scsi_cmnd *SCpnt,
> SCp.ptr : buffer pointer
> SCp.this_residual : buffer length
> SCp.buffer : next buffer
> - SCp.buffers_residual : left buffers in list
> SCp.phase : current state of the command */
>
> if ((phase & resetting) || !scsi_sglist(SCpnt)) {
> @@ -956,13 +955,11 @@ static int aha152x_internal_queue(struct scsi_cmnd *SCpnt,
> SCpnt->SCp.this_residual = 0;
> scsi_set_resid(SCpnt, 0);
> SCpnt->SCp.buffer = NULL;
> - SCpnt->SCp.buffers_residual = 0;
> } else {
> scsi_set_resid(SCpnt, scsi_bufflen(SCpnt));
> SCpnt->SCp.buffer = scsi_sglist(SCpnt);
> SCpnt->SCp.ptr = SG_ADDRESS(SCpnt->SCp.buffer);
> SCpnt->SCp.this_residual = SCpnt->SCp.buffer->length;
> - SCpnt->SCp.buffers_residual = scsi_sg_count(SCpnt) - 1;
> }
>
> DO_LOCK(flags);
> @@ -2030,10 +2027,9 @@ static void datai_run(struct Scsi_Host *shpnt)
> }
>
> if (CURRENT_SC->SCp.this_residual == 0 &&
> - CURRENT_SC->SCp.buffers_residual > 0) {
> + !sg_is_last(CURRENT_SC->SCp.buffer)) {
> /* advance to next buffer */
> - CURRENT_SC->SCp.buffers_residual--;
> - CURRENT_SC->SCp.buffer++;
> + CURRENT_SC->SCp.buffer = sg_next(CURRENT_SC->SCp.buffer);
> CURRENT_SC->SCp.ptr = SG_ADDRESS(CURRENT_SC->SCp.buffer);
> CURRENT_SC->SCp.this_residual = CURRENT_SC->SCp.buffer->length;
> }
> @@ -2136,10 +2132,10 @@ static void datao_run(struct Scsi_Host *shpnt)
> CMD_INC_RESID(CURRENT_SC, -2 * data_count);
> }
>
> - if(CURRENT_SC->SCp.this_residual==0 && CURRENT_SC->SCp.buffers_residual>0) {
> + if (CURRENT_SC->SCp.this_residual == 0 &&
> + !sg_is_last(CURRENT_SC->SCp.buffer)) {
> /* advance to next buffer */
> - CURRENT_SC->SCp.buffers_residual--;
> - CURRENT_SC->SCp.buffer++;
> + CURRENT_SC->SCp.buffer = sg_next(CURRENT_SC->SCp.buffer);
> CURRENT_SC->SCp.ptr = SG_ADDRESS(CURRENT_SC->SCp.buffer);
> CURRENT_SC->SCp.this_residual = CURRENT_SC->SCp.buffer->length;
> }
> @@ -2158,22 +2154,26 @@ static void datao_run(struct Scsi_Host *shpnt)
> static void datao_end(struct Scsi_Host *shpnt)
> {
> if(TESTLO(DMASTAT, DFIFOEMP)) {
> - int data_count = (DATA_LEN - scsi_get_resid(CURRENT_SC)) -
> - GETSTCNT();
> + u32 datao_cnt = GETSTCNT();
> + int datao_out = DATA_LEN - scsi_get_resid(CURRENT_SC);
> + int done;
> + struct scatterlist *sg = scsi_sglist(CURRENT_SC);
>
> - CMD_INC_RESID(CURRENT_SC, data_count);
> + CMD_INC_RESID(CURRENT_SC, datao_out - datao_cnt);
>
> - data_count -= CURRENT_SC->SCp.ptr -
> - SG_ADDRESS(CURRENT_SC->SCp.buffer);
> - while(data_count>0) {
> - CURRENT_SC->SCp.buffer--;
> - CURRENT_SC->SCp.buffers_residual++;
> - data_count -= CURRENT_SC->SCp.buffer->length;
> + done = scsi_bufflen(CURRENT_SC) - scsi_get_resid(CURRENT_SC);
> + /* Locate the first SG entry not yet sent */
> + while (done > 0 && !sg_is_last(sg)) {
> + if (done < sg->length)
> + break;
> + done -= sg->length;
> + sg = sg_next(sg);
> }
> - CURRENT_SC->SCp.ptr = SG_ADDRESS(CURRENT_SC->SCp.buffer) -
> - data_count;
> - CURRENT_SC->SCp.this_residual = CURRENT_SC->SCp.buffer->length +
> - data_count;
> +
> + CURRENT_SC->SCp.buffer = sg;
> + CURRENT_SC->SCp.ptr = SG_ADDRESS(CURRENT_SC->SCp.buffer) + done;
> + CURRENT_SC->SCp.this_residual = CURRENT_SC->SCp.buffer->length -
> + done;
> }
>
> SETPORT(SXFRCTL0, CH1|CLRCH1|CLRSTCNT);
> @@ -2501,7 +2501,7 @@ static void get_command(struct seq_file *m, struct scsi_cmnd * ptr)
>
> seq_printf(m, "); resid=%d; residual=%d; buffers=%d; phase |",
> scsi_get_resid(ptr), ptr->SCp.this_residual,
> - ptr->SCp.buffers_residual);
> + sg_nents(ptr->SCp.buffer) - 1);
>
> if (ptr->SCp.phase & not_issued)
> seq_puts(m, "not issued|");
>
